public static void Main()
{
HDict <ConcreteJsonWriteRelation> dict = new HDict <ConcreteJsonWriteRelation>();
JsonWrite0 <int, ConcreteJsonWriteRelation> w = new IntJsonWrite2 <ConcreteJsonWriteRelation>();
HDict <ConcreteJsonWriteRelation> dict2 = dict.Add(new Type <int>(), w);
Console.WriteLine(1.ToJsonString(dict));
Console.WriteLine(true.ToJsonString(dict));
Console.WriteLine(ListType.To(new List <int> {
1, 2, 3
}).ToJsonString(dict2));
Console.WriteLine(new MyStruct(123, false).ToJsonString(dict));
// compile time error!
// Console.WriteLine( "hoge".ToJsonString(dict) );
}
